Once an output descriptor name exists in a job step, the job step cannot have another descriptor with the same name. Thus, if a descriptor name is produced within a job step by an OUTPUT JCL statement or by an invocation of dynamic output, you cannot invoke OUTADD in that job step to create another descriptor with the same name. An output descriptor that is created dynamically (by OUTADD) in a particular job step cannot be referenced outside the job step.
When you use OUTADD to create output descriptors in a program that also uses checkpoint/restart, you must observe the restrictions that are described in z/OS DFSMSdfp Checkpoint/Restart.